905
FXUS61 KAKQ 021903
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
303 PM EDT Thu May 2 2024

.SYNOPSIS...
A backdoor cold front pushes into the Maryland eastern shore
late tonight, then inland across the remainder of the area on
Friday, leading to much cooler conditions at the coast. Rain
chances return Friday evening through Sunday as a series of
disturbances impact the region. Summerlike conditions come to
the area by the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 230 PM EDT Thursday...

Very quiet tonight with high pressure overhead.
Guidance suggests that the front over southern New York and PA will
move across the MD eastern shore late tonight allowing winds to back
to the NE with an increase in clouds late. But otherwise this front
will be of little consequence tonight. Do not think fog will be an
issue over land tonight given that we had a day of full sunshine
today likely allowing any excessive moisture to burn off. Lows will
be in the mid-upper 50s across the MD eastern shore and lower 60s
elsewhere.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
As of 230 PM EDT Thursday...

The backdoor front will continue to move SW across the region on
Friday. Models have good timing on the front, reaching the VA
eastern shore and SE VA Friday morning, the RIC metro around lunch
time, then to the southern Piedmont of VA by late afternoon.
Latest CAMs show some pop up showers for areas mainly west of
I-95 as the front moves SW. Have therefore included slight
chance PoPs for the afternoon in that same general region. Could
not completely rule out thunder as the HREF mean SBCAPE shows
500-1000 J/KG. There will be quite a gradient of temperatures
across the area, with Ocean City likely staying in the 50s
through the day, while areas in the southern Virginia Piedmont
will reach upper 80s for highs. The temperature will likely
remain steady or even fall slightly once the front passes your
location tomorrow.

Improved moisture return sets up for Friday night and continues into
Saturday. Best moisture stays mainly over the Piedmont, and will
also be helped by overrunning over top the low level wedge. The
better moisture and lift moves in on Saturday as the 850mb winds
increase and have kept likely PoPs over the Piedmont, tapering to
low chance at the coast. Even at the coast though, it will not be
terribly pleasant in the morning with onshore flow, low clouds
and the potential for drizzle into Saturday morning. Have
generally undercut the NBM highs for Saturday, especially
across the far NW. Highs will range from the mid 60s (or
possibly even lower) in the NW piedmont counties, to lower 80s
across the far south where some afternoon sunshine is possible.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 230 PM EDT Thursday...

The backdoor front will attempt to move back north on Sunday as the
Ohio valley system approaches from the west. Showers may be more
widespread on Sunday due to a weak disturbance aloft lowering
heights across the region. Best moisture and still expected
along/west of I-95.  As such, have continued with likely/categorical
PoPs over the west on Sunday, tapering to chance PoPs at the coast.
Highs expected to be warmer than Saturday in the mid 70s to lower
80s, warmest SE VA/NC NC.

By Monday, the warm front will be well north of the area. However,
the system over the Ohio Valley will be moving through during the
day. Expect another round of showers/storms mainly during Monday
afternoon into Monday evening as a stronger upper disturbance moves
through in the W-NW flow aloft. Slightly more instability on Monday
vs Sunday so more thunderstorms are expected.

We get into an almost summertime pattern by Tuesday as the ridge
aloft builds overhead with afternoon/evening showers and
thunderstorms each day being triggered by the lee side trough. The
GFS and ECMWF both suggest the ridge breaks down slightly by Wed/Thu
with stronger 500mb flow of up to 50 kt by Wed afternoon. Along with
this, those models suggest weak short waves (likely of mesoscale
origin from convection over the Ohio Valley and central plains)
moving through the area. Although we are talking about days 6 and 7,
the relatively strong upper flow combined with relative steep mid
level lapse rates of up to 7 C/km would suggest the possibility of
severe weather. In fact, the CSU Machine Learning Probabilities
suggest a slight risk for severe weather on Wednesday and again on
Thursday. We have plenty of time to monitor this, but the area may
become a little more active by the end of next week.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
As of 130 PM Thursday...

VFR conditions with light winds expected through tomorrow morning. A
backdoor cold front will move into the Maryland Eastern Shore late
tonight, allowing winds to turn NE by Fri morning. This front will
continue to slowly move SW on Friday, perhaps reaching the other
terminals by 18z. Some forecast guidance suggest that SBY may see
MVFR cigs after 15z tomorrow behind the front and have included that
in the terminal fcst.

Outlook...Sub-VFR conditions expected at times through through the
weekend and even into early next week due to an unsettled weather
pattern through Monday with chances for rain/storms each day. A
summerlike pattern returns by Tuesday with chances for storms each
afternoon/evening.

&&

.MARINE...
As of 300 PM EDT Thursday...

Key Messages:

- Small craft advisories have been issued for the Chesapeake Bay
Friday behind a backdoor cold front.

Benign conditions on the marine front this afternoon with winds
having recently shifted to the S/SSE. Speeds are 15 kt or less. Very
shallow marine fog has also been noted on the ocean, mainly N of the
Cape Charles. Have a dense fog advisory for these zones through 4 PM
this afternoon. Otherwise, light winds are expected through Friday
morning with a light pressure gradient across the area. E/NE winds
increase abruptly later Friday morning as a backdoor cold front
moves from NE to SW through the waters. Winds increase to 15-20 kt
with gusts to around 25 kt. A brief period of gusts to 30 kt are
possible right behind the front early Fri aftn. The highest
confidence in meeting small craft criteria is in the southern bay,
though am rather confident the entirety of the bay should approach
criteria. Have therefore issued a small craft advisory for these
areas from Fri morning/aftn into Fri night. The bay N of New Point
Comfort starts at 10 AM Fri, with the lower bay, mouth of the bay,
and lower James starting at 1 PM Fri. On the ocean, wind gusts and
wave heights on average should stay below 25 kt and 5 ft,
respectively. Should note that onshore flow conditions tend to
elevate seas a bit higher than guidance, so will monitor this over
the next 12-24 hrs. As of now, seas are forecast to increase to 3-4
ft. The best chance of 5 ft seas would be N of Cape Charles.
Easterly winds subside some Sat morning, but will remain around ~15
kt. Wind speeds tick up again Sat aftn with another chance at SCA
conditions. Seas remain 3-4 ft with waves 2-3 ft in the
bay/rivers/sound.

The front lifts back N on Sunday, shifting winds to the S/SSE. SSW
winds return for Monday through the middle of next week (but remain
sub-SCA).

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory from 10 AM Friday to 1 AM EDT Saturday
     for ANZ630-631.
     Small Craft Advisory from 1 PM Friday to 1 AM EDT Saturday for
     ANZ632-634-638.
     Dense Fog Advisory until 4 PM EDT this afternoon for ANZ650-
     652-654.

&&

$$

SYNOPSIS...MRD
NEAR TERM...MRD
SHORT TERM...MRD
LONG TERM...MRD
AVIATION...AJB/MRD
MARINE...SW